1. Field
The information disclosed in this patent relates to a portable exercise device that may work to strengthen and rehabilitate the arm and in particular the shoulder.
2. Background Information
In human anatomy, the shoulder is that part of the body where the arm attaches to the torso. Articulations between the upper arm bone, the collarbone, the shoulder blade, and the associated muscles, ligaments, and tendons that attach these three bones together make up the shoulder joints. A properly working shoulder is flexible over a wide range of motion required in the arms and hands. However, this tremendous range of motion also makes the shoulder extremely unstable, far more prone to dislocation and injury than other joints.
The shoulder is one of the most commonly injured joints in the body. This is due to the complex arrangement of the surrounding ligaments and tendon muscle groups that are needed for, first, stabilization of the joint, and then, second, for providing a coordinated movement of the shoulder through a three-dimensional space at varying velocities of acceleration and deceleration. Unlike the hip joint, which includes a bone socket for support, the shoulder lacks a bone socket and relies solely on the surrounding muscles, tendons, and ligaments for support and stabilization.
The rotator cuff is an anatomical term given to the group of small muscles and their tendons that act to stabilize the shoulder. Moving the shoulder through space requires the coordinated activation and deactivation of the rotator cuff while permitting the larger power muscle group, such as the deltoid and pectoral muscles, to provide the needed acceleration and torque when engaged in any type of throwing or swinging activity. Sports that place high demands on such coordinated efforts include baseball, football, tennis, volleyball, golf, and racquetball, just to name a few. Essentially any activity that requires the use of the arm needs shoulder stability and control to function. These may be anything from hanging a jacket on the coat rack to playing ping-pong or basketball, or holding onto the rope while water skiing.
Shoulder exercises typically are intended to strengthen the shoulder, thus preventing injury; or to rehabilitate the shoulder after injury or surgery. The most basic equipment for the aid of strengthening of the shoulder is the dumbbell. Free-weights allow front to back, up and down, or side-to-side exercises. The larger power muscles are strengthened while the small stabilizing muscle groups are ignored. Exercise rubber bands or tubes, and cable weight systems function similar to free weights. That is, unidirectional strengthening of muscle groups. By varying the technique of how the tube or the cable is pulled, a person may exercise some specific rotator cuff muscles. However, these exercise movements work on only a few muscle groups at a time in a unidirectional manner without the ability to vary the level of intensity during the workout period.
A more interesting training device, the Bodyblade® (U.S. Pat. No. 5,147,262), does require the coordinated efforts of a few opposing muscle groups during the exercise routine. It also has a benefit of allowing the individual to vary the intensity of the workout while in the midst of doing the workout by varying the speed or magnitude at which one moves the Bodyblade®. However, again, it lacks multidirectional, proprioceptive training of all of the surrounding shoulder muscle groups at the same time. The Bodyblade® moves only in a unidirectional plane, i.e. side to side or up and down.
The Dyna-Flex Pro Gyro Trainer® or the Dyna-Flex Power Ball Gyro Trainer® are hand-held devices that use gyroscopic principle for strengthening primarily of the wrist and forearm. However, these trainers include limitations such as (1) that the resistance cannot be varied much during use as it is preset predominantly by the pull of the cord in the rotor groove, and (2) very little resistance or workout ability can be transferred to the shoulder joint. The Center Force Golf Dyna Max Core Gyro Trainer®, although an excellent device, it again strengthens primarily the wrist and forearm grip strengths. The shoulder muscle groups are not isolated for dedicated strengthening because this device has to be gripped onto tightly by the hand, thus the effect of the exercise is directed to the hand, wrist, and forearm via the gripping force that is required while holding onto this device.
The most expensive and complex piece of machinery that physical therapy and rehabilitation centers posses is the Upper Body Ergometer® (UBE). This essentially is a freestanding machine with two crank peddles that allow the user to peddle through as if “riding the bicycle” with the arms. Variable resistances may be set. Drawbacks of the UBE include its expense, non-portability, and lack of variability for training of different shoulder muscle groups.
As noted above, traditional shoulder exercise devices provide exercises in a unidirectional—side-to-side or up and down—manner. However, the shoulder functions in a complex multidirectional manner through three-dimensional space. Although traditional exercises provide some benefits, they lack an ability to strengthen and educate the shoulder in a multidirectional manner that is needed for the numerous types of demands placed upon the shoulder by an infinite number of types of activities. Thus, there is a need for an improved shoulder exercise device for shoulder strengthening and rehabilitation.